--- a/src/expanded.c
+++ b/src/expanded.c
@@ -18,9 +18,9 @@
  * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+#include <string.h>
 #include "tree.h"
 #include "cli.h"
-#define NULL 0
 
 #include "evilloop.h"
 #include "ctype.h"